1. Field of the Invention
The present invention relates generally to controlling the flow of fluid through a deformable tube and more particularly to a tube clamp adapted to selectively pinch the tube to thereby occlude the flow of fluid therethrough.
2. Description of the Prior Art
Numerous devices have been developed for occluding the flow of fluid through deformable tubes. Such devices have included cams for moving pinching arms against the tube to pinch the tube between the arms and a mandrel. Other devices utilize an eccentric to squeeze the tube against a mandrel to thereby occlude the flow of fluid therethrough, while still other devices utilize laterally moving rams such as may be activated by a solenoid to compress the tube against a mandrel to occlude the flow of fluid therethrough. There are numerous examples of such devices in the patented art of the United States.
Devices for occluding the flow of fluid through a deformable tube are used in the field of blood apheresis wherein a peristaltic pump is utilized to dispense citrate as an anticoagulant into a blood stream through a deformable tube. It is critical that the citrate be dispensed in precise quantities and, accordingly, a dependable system for satisfactorily occluding the flow of citrate through the tube is highly desirable.
In current apheresis equipment, the deformable tubes utilized in dispensing citrate are typically occluded by use of a solenoid actuated ram that pinches the tube against a mandrel disposed on the opposite side of the tube. Such devices have a number of drawbacks, however, in that they are loud when operated, the ram is preset to move a predesignated distance so that if the wall thickness of a deformable tube varies, the tube may not be fully occluded by the ram, the solenoids abruptly pinch the tube and therefore may cause damage thereto in prolonged usage and solenoids are known to have relatively high power consumption. In addition, solenoids generate more heat than is desired.
Accordingly, it would be desirable in apheresis systems to have a dependable mechanism for occluding the flow of citrate through a deformable tube which is quiet in operation, does not generate a lot of heat, has a relatively low power requirement, and occludes the flow of fluid through the tube in a manner such that the tube has a longer life. It is to satisfy these needs that the tube clamp of the present invention has been developed.